The invention relates to a printer comprising a guide device for transporting a record carrier, by means of a transport roller, to an elongated, flat supporting surface which adjoins the transport roller along one of the surface long sides, viewed in the transport direction of the record carrier, and along which surface a printing head is displaceable. A ruler presses the record carrier away from the face of the printing head before it reaches the area of the printing head. In a printer of this kind which is known, for example, from German Offenlegungsschrift No. 28 29 827, the record carrier should rest as flatly as possible on the supporting surface in order to keep the distance between the record carrier and the printing head as constant as possible; this is important notably when the printing head is an ink jet printing head. In the printer which is known from Offenlegungsschrift No. 28 29 827, to which U.S. Pat. No. 4,294,556 corresponds, the supporting surface tangentially adjoins the transport roller and the record carrier is pressed against the transport roller by means of a member or ruler directly before the separation from the transport roller. It has been found that the record carrier does not rest flatly on the supporting surface in all circumstances in such a guide device.